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Duncan R, Hershey JW. Regulation of initiation factors during translational repression caused by serum depletion. Covalent modification. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(18)89049-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Jagus R, Anderson WF, Safer B. The regulation of initiation of mammalian protein synthesis. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1981; 25:127-85. [PMID: 6164076 DOI: 10.1016/s0079-6603(08)60484-5] [Citation(s) in RCA: 228] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Marcus DL, Ibrahim NG, Gruenspecht N, Freedman ML. Iron requirement for isolated rat liver mitochondrial protein synthesis. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 607:136-44. [PMID: 7370259 DOI: 10.1016/0005-2787(80)90227-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Isolated rat liver mitochondrial protein synthesis was severly inhibited by alpha, alpha-dipyridyl (a ferrous iron-chelating agent), chloramphenicol and hemin (10(-7) M or greater). In contrast, gamma, gamma-dipyridyl (a non-iron-chelating analogue of alpha, alpha-dipyridyl), cycloheximide and lower concentrations of hemin were non-inhibitory. The inhibitory action of alpha, alpha-dipyridyl was reversed by addition of Fe(NH4)2(SO4)2 while ZnCl2, CuCl2 and CoCl2 were ineffective. Hemin, however, did not protect against the alpha, alpha-dipyridyl inhibition of mitochondrial protein synthesis. These results indicate that ferrous iron is required for mitochondrial protein synthesis and suggests that it is through a mechanism independent of hemin concentration.
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Spieler PJ, Ibrahim NG, Freedman ML. Heat inhibition of reticulocyte protein synthesis. Evidence for a mechanism independent of the hemin-controlled repressor. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 518:366-79. [PMID: 656422 DOI: 10.1016/0005-2787(78)90193-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Incubation of rabbit reticulocytes at 45 degrees C results in a prompt but reversible decrease in protein synthesis and a concomitant conversion of polyribosomes to smaller aggregates. These effects occur even in the presence of 100 micrometer hemin in the incubation medium. There is also inhibition of heme synthesis but this occurs at a later time than the effect on protein synthesis. The inhibtion of heme synthesis results from a decrease in activity of beta-aminolevulinic acid synthetase. This decrease of heme synthesis appears to be secondary to the inhibition of protein synthesis with resultant accumulation of intramitochondrial heme (which will decrease beta-aminolevulinic acid synthetase activity). An inhibitor of reticulocyte cell-free protein synthesis formed in the postribosomal supernatants of cells incubated at both 45 and 37 degrees C but not at 0 degrees C. No temporal or quantitative differences in the amount of this inhibitor from cells treated at either 37 or 45 degrees C was apparent. The inhibitor was not found in the fraction where the hemin-controlled repressor is isolated. It is concluded that heat inactivation of intact reticulocyte protein synthesis does not depend upon a decrease in heme synthesis, heme concentration or generation of the hemin-controlled repressor. Furthermore, it appears that the inhibitor formed in the post-ribosomal supernatant cannot be the sole cause of the heat inhibition of protein synthesis.
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Freedman ML, Spieler PJ, Rosman J, Wildman JM. Cyclic AMP maintenance of rabbit reticulocyte haem and protein synthesis in the presence of ethanol and benzene. Br J Haematol 1977; 37:179-94. [PMID: 203310 DOI: 10.1111/j.1365-2141.1977.tb06834.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Ponka P, Neuwirt J, Borová J, Fuchs O. Control of iron delivery to haemoglobin in erythroid cells. CIBA FOUNDATION SYMPOSIUM 1976:167-200. [PMID: 1052029 DOI: 10.1002/9780470720325.ch9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This paper reviews and reports the results of experiments on the mechanism by which iron is delivered from extracellular transferrin to reticulocyte mitochondria in which haem is synthesized. It is suggested that transferrin donates the iron directly to mitochondria. Transferrin seems to be bound to mitochondria during the process of iron release. When the release of iron from transferrin is blocked by haem, the iron-transferrin complex remains bound to mitochondria so that the total amount of transferrin molecules associated with mitochondria increases in haem-treated reticulocytes. This also leads to an increase in the number of transferrin molecules in the cytosol. In haem-deficient reticulocytes, the rate of dissociation of iron from transferrin is accelerated and the uptake of iron by mitochondria is increased. When the synthesis of haem is inhibited, the non-haem iron in the cytosol (i.e. mainly low-molecular-weight and ferritin iron) comes from mitochondria. Greater amounts of non-haem iron can also be induced in reticulocytes incubated with highly saturated transferrin but, in this case, iron does not seem to be accumulated in mitochondria. These results represent an experimental basis for the elucidation of the excessive non-haem iron accumulation in erythroid cells observed in various clinical conditions.
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Giloh H, Schochot L, Mager J. Inhibition of peptide chain initiation in lysates from ATP-depleted cells. II. Studies on the mechanism of the lesion and its relation to similar alterations caused by oxidized glutathione and hemin deprivation. BIOCHIMICA ET BIOPHYSICA ACTA 1975; 414:309-20. [PMID: 173394 DOI: 10.1016/0005-2787(75)90169-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The impairment of peptide chain initiation in lysates from ATP-depleted rabbit reticulocytes is accompanied by a loss of their ability to form the 40 S methionyl-tRNAfMet complex with a resultant failure to promote the AUG codon-dependent combination of the complex with the 60 S ribosomal subunit. These partial initiation reactions, as well as the overall protein-synthetic activity of the defective lysates could be restored by addition of a 0.5 M KC1 ribosomal extract or normal postribosomal supernatant or a 40-70% (NH4)2-SO4 fraction derived from it. Alternatively, reactivation of the impaired lysates could be achieved by supplementation with millimolar amounts of cyclic AMP or certain purine derivatives. The same subcellular fractions, as well as cyclic AMP or purine derivatives were also capable of overcoming the inhibition caused by incubating reticulocyte lysates in the presence of oxidized glutathione or in the absence of hemin. Severe intracellular ATP deprivation resulted in accumulation of a soluble translational inhibitor in the postribosomal fraction, thus resembling the parallel phenomenon described in hemin-deprived lysates. The striking similarities between the three kinds of inhibition studied by us point to an identical site of the underlying biochemical lesion, despite the different mechanisms mediating their induction.
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Freedman ML, Cohen HS, Rosman J, Forte FJ. Ethanol inhibition of reticulocyte protein synthesis: the role of haem. Br J Haematol 1975; 30:351-63. [PMID: 1201218 DOI: 10.1111/j.1365-2141.1975.tb00551.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Ethanol, in concentrations of 0.05-0.8 M, inhibited intact human and rabbit reticulocyte protein synthesis in the presence of iron-transferrin for endogenous haem synthesis. Associated with this effect there was a conversion of polyribosomes to monoribosomes and a decreased incorporation of radioactive leucine into nascent globin chains. When physiological levels of ethanol (0.05-0.1 M) were used, these effects were prevented by incubation with 50 muM haemin and reversed by removing the alcohol and reincubating with iron-transferrin or haemin. The polyribosomal disaggregation was also prevented by stopping ribosomal movement with 5 mM cycloheximide. Neither ATP nor GSH levels were altered in the presence of ethanol. When non-physiological levels of 0.8 M ethanol were used, haemin did not prevent the inhibition of protein synthesis. Likewise, in the rabbit reticulocyte cell-free lysate system containing haemin inhibition was noted at concentrations greater than 0.05 M ethanol. The polyribosomal disaggregation in reticulocytes incubated with 0.8 M ethanol was associated with decreased dissociation of monoribosomes into subunits. Similarly, when ribosomes were directly suspended cell-free in 0.1 or 0.8 M ethanol there was a decreased percentage of subunits. These results indicate that physiological concentrations of ethanol inhibit initiation of reticulocyte protein synthesis secondary to a block in haem synthesis. When intact cells are exposed to high non-physiological concentrations of ethanol the inhibition is secondary to decreased ribosomal dissociation. The cell-free lysate inhibition is also through this effect on ribosomal dissociation. This study supports the view that alcohol is a direct toxin to developing red cell precursors via its effect on mitochondrial haem synthesis. The physiological role of the decreased dissociation of monoribosomes into subunits is not yet clear.
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Cole RJ, Garlick J, Tarbutt RG. Disturbed haem and globin synthesis in reticulocytes of prenatal flexed-tailed (f-f) anaemic mice. Genet Res (Camb) 1974; 23:125-35. [PMID: 4425203 DOI: 10.1017/s0016672300014749] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
SUMMARYHaem synthetase activity and co-ordination of α- and β-globin chain synthesis have been investigated in prenatal reticulocytes of congenic FL/4Re +/+Lvb/Lvband FL/1 Ref/f Lvb/Lvb, mice, which have a marked hypochromic, microcytic, siderocytic anaemia, with reduced erythrocyte numbers at birth, and also in other stocks bearing theflesion. Haem synthetase activity inf/freticulocyte homogenates was similar to that in normal cells but was markedly dependent on protoporphyrin added to the homogenate, while activity in normal cell homogenates was relatively independent of added precursor. In cultured normal prenatal reticulocytes α- and β-globin was synthesized in approximately equal amounts during a 4 h labelling period, but inf/freticulocytes there was an approximate 50% deficiency in β-globin chain synthesis. This deficiency could be repaired by added haem but not by protoporphyrin. Such a lesion is quantitatively consistent with the observed hypochromia of neonatalf/ferythrocytes. The relationship of this abnormality to effects of theflocus on early erythropoietic precursor cells is discussed.
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Wolf JL, Mason RG, Honig GR. Regulation of hemoglobin beta-chain synthesis in bone marrow erythroid cells by alpha chains. Proc Natl Acad Sci U S A 1973; 70:3405-9. [PMID: 4519634 PMCID: PMC427246 DOI: 10.1073/pnas.70.12.3405] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Synthesis of alpha and beta chains of hemoglobin was studied in vitro in intact reticulocytes and bone marrow cells. The cells were from rabbits having a variant form of hemoglobin in which L-isoleucine is in the alpha but not in the beta chains. This characteristic permitted a selective inhibition of alpha-chain synthesis to be produced by addition to the incubation medium of L-O-methylthreonine, an inhibitor of protein synthesis that is a specific antagonist of L-isoleucine. In studies with reticulocytes, 25 mM L-O-methylthreonine produced a 60-70% inhibition of alpha-chain synthesis, but beta-chain synthesis was unaffected even after incubation times for 4 hr. Because reticulocytes contain a pool of uncombined alpha chains which might have obscured the demonstration of an alpha chain-dependent mechanism for beta-chain synthesis, subsequent studies were done with bone marrow cells. The latter had little or no detectable alpha-chain pool. A substantial inhibition of alpha-chain synthesis by the bone marrow cells was produced by the isoleucine antagonist but was also accompanied by a significantly decreased rate of beta-chain synthesis. These findings suggest that the coordinated synthesis of the complementary alpha- and beta-globin chains of hemoglobin may reflect in part a modifying effect of alpha-chain synthesis on the synthesis of beta chains.
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Schulman HM, Martinez-Medellin J, Sidloi R. The labilization of hemoglobin by cobalt. Its effect on globin synthesis in reticulocytes. EUROPEAN JOURNAL OF BIOCHEMISTRY 1973; 37:178-84. [PMID: 4729425 DOI: 10.1111/j.1432-1033.1973.tb02973.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Regulation of Synthesis of Non-Globin Proteins in Cell-free Extracts of Rabbit Reticulocytes. J Biol Chem 1973. [DOI: 10.1016/s0021-9258(19)43961-6] [Citation(s) in RCA: 91] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Gross M, Rabinovitz M. Control of globin synthesis by hemin: factors influencing formation of an inhibitor of globin chain initiation in reticulocyte lysates. BIOCHIMICA ET BIOPHYSICA ACTA 1972; 287:340-52. [PMID: 4680051 DOI: 10.1016/0005-2787(72)90383-8] [Citation(s) in RCA: 122] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Freedman ML, Velez R, Mucha J. Resistance of messenger RNA-bound ribosomes to proteolytic dissociation. Exp Cell Res 1972; 72:431-5. [PMID: 5037928 DOI: 10.1016/0014-4827(72)90011-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Gross M, Rabinovitz M. Control of globin synthesis in cell-free preparations of reticulocytes by formation of a translational repressor that is inactivated by hemin. Proc Natl Acad Sci U S A 1972; 69:1565-8. [PMID: 4504369 PMCID: PMC426749 DOI: 10.1073/pnas.69.6.1565] [Citation(s) in RCA: 103] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The control of globin synthesis by hemin in cell-free preparations of rabbit reticulocytes is mediated by an inhibitor (translational repressor) of globin chain initiation that is inactivated by hemin. When the ribosome-free supernatant fraction is warmed at 34 degrees without hemin, it quickly acquires the ability to inhibit a fresh cell-free preparation. If the warmed supernatant fraction is further incubated with hemin, its inhibitory activity is lost. This reversible inhibitor, which is observable only during the early period of incubation without hemin, is distinct from an irreversible inhibitor that becomes prevalent during longer incubations. The reversible inhibitor may be an intermediate in the formation of the irreversible inhibitor. The sensitivity of the reversible inhibitor to inactivation by hemin, which permits resumption of globin synthesis in both intact cells and lysates, indicates that the inhibitor is a physiological regulator.
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Maxwell CR, Kamper CS, Rabinovitz M. Hemin control of globin synthesis: an assay for the inhibitor formed in the absence of hemin and some characteristics of its formation. J Mol Biol 1971; 58:317-27. [PMID: 5088932 DOI: 10.1016/0022-2836(71)90249-x] [Citation(s) in RCA: 119] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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White JM, Brain MC, Ali MA. Globin synthesis in sideroblastic anaemia. I. Alpha and beta peptide chain synthesis. Br J Haematol 1971; 20:263-75. [PMID: 5552358 DOI: 10.1111/j.1365-2141.1971.tb07037.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Velez R, Farrell NL, Freedman ML. Selective proteolytic dissociation of rabbit reticulocyte single ribosomes not attached to messenger RNA. BIOCHIMICA ET BIOPHYSICA ACTA 1971; 228:719-27. [PMID: 5572611 DOI: 10.1016/0005-2787(71)90736-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Hammel-Dupont CL, Bessman SP. The stimulation of hemoglobin synthesis by porphyrins. BIOCHEMICAL MEDICINE 1970; 4:55-60. [PMID: 5524059 DOI: 10.1016/0006-2944(70)90102-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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25
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González-Cadavid NF, Wecksler M, Bravo M. Stimulating effect of haemin on the synthesis of cytochrome c by liver slices. FEBS Lett 1970; 7:248-250. [PMID: 11947483 DOI: 10.1016/0014-5793(70)80172-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- N F. González-Cadavid
- Departamento de Biologia Celular, Facultad de Ciencias, Universidad Central, Caracas, Venezuela
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Waxman HS. Stimulation of globin synthesis: relative responsiveness of reticulocytes and nucleated erythroid cells. J Clin Invest 1970; 49:701-7. [PMID: 5443172 PMCID: PMC322525 DOI: 10.1172/jci106282] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The effects of iron, cobalt, hemin, and plasma on hemoglobin synthesis by suspensions of rabbit reticulocytes and nucleated bone marrow cells were studied. L-Leucine-(14)C and sodium pyruvate-3-(14)C were employed to measure globin and heme synthesis, respectively. Normal plasma (or serum) was found to stimulate the rate of globin synthesis in both systems. The stimulatory effects of iron and hemin were additive to those of plasma or serum only in the reticulocytes. Cobaltous ion, at concentrations less than 1.0 mmole/liter, was found to stimulate globin synthesis by reticulocytes as effectively as ferrous ion; cobalt was inhibitory only at concentrations greater than 3.0-5.0 mmoles/liter. Heme synthesis by reticulocytes was inhibited at all concentrations employed (0.2-5.0 mmoles/liter). In bone marrow nucleated erythroid cells, globin synthesis was markedly enhanced by exogenous hemin. In contrast to reticulocytes, however, bone marrow cells were unresponsive to either cobalt or transferrin-bound iron. Possible implications of these findings on regulation of the rate and mechanism of iron uptake and hemoglobin synthesis in vivo are discussed.
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Maxwell CR, Rabinovitz M. Evidence for an inhibitor in the control of globin synthesis by hemin in a reticulocyte lysate. Biochem Biophys Res Commun 1969; 35:79-85. [PMID: 5779151 DOI: 10.1016/0006-291x(69)90485-9] [Citation(s) in RCA: 91] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Marks PA, Fantoni A, De la Chapelle A. Hemoglobin synthesis and differentiation of erythroid cells. VITAMINS AND HORMONES 1969; 26:331-55. [PMID: 4887753 DOI: 10.1016/s0083-6729(08)60760-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Schulman HM, Jobe A. The inhibition of heme and globin synthesis by cobalt in rabbit reticulocytes and bone marrow. BIOCHIMICA ET BIOPHYSICA ACTA 1968; 169:241-7. [PMID: 5727135 DOI: 10.1016/0005-2787(68)90026-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Freedman ML, Fisher JM, Rabinovitz M. Puromycin interference of reticulocyte polyribosome disaggregation caused by tryptophan deficiency. J Mol Biol 1968; 33:315-8. [PMID: 5646650 DOI: 10.1016/0022-2836(68)90297-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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